Call-waiting service is commercially available in many parts of the country. The call-waiting service provides an audible tone signal to a subscriber while his telephone is in use, letting him know that another caller is trying to reach his station. The service enables the subscriber to switch alternately between the party he was initially connected to and the new caller, simply by depressing his hookswitch momentarily. The party he is not talking with at any moment is placed on hold. If the first party disconnects, the next caller appears in his place and the operation may be repeated.
Three-way calling service is also commercially available in many parts of the country and it enables a subscriber to establish a three-way conference call. As discussed in U.S. Pat. No. 3,626,107 to Loren K. Armstrong and George R. Bergquist, the subscriber interrupts a call in progress at his station by momentarily depressing his hookswitch. The party at the other end of the line is automatically placed on hold and the subsciber is given a dial tone. The subscriber then dials the desired third party. Once he has dialed the third party's number, he may set up the conference call at any time, either immediately, or after he has spoken privately with the third party, by another flash of his hookswitch. A third flash of his hookswitch disconnects the third party. Three-way calling is under control of the subscriber, and during times when it is in use, call-waiting service is inhibited. Similarly, when call-waiting service is in use, three-way calling service is inhibited.
A recent version of caller identification with call-waiting is discussed in U.S. Pat. No. 5,263,084 to Chaput et al. which is directed to providing third party identification to a called party's telephone set while the latter is off-hook. From another perspective, the invention provides a method of transmitting caller identification information of a calling third party between a central office and a called customer premises equipment having receiving and transmitting transducers while the called customer premises equipment is presenting an off-hook condition to the called customer loop, comprising the steps of sending an alerting tone signal having predetermined characteristics from the central office to the called customer premises equipment to alert the latter that the central office wishes to send caller identification information relating to the calling third party. In response to the alerting tone signal, the called customer premises equipment mutes its associated handset for a predetermined duration of time corresponding to at least the duration of the calling third party identification information to be transmitted between the central office and the caller customer premises equipment. The called customer premises equipment receives and displays to the called customer during a silent interval of the alerting tone signal the identification information of the calling third party, thereby allowing the called customer to either accept or reject the call from the third party in the conventional manner but also based on the displayed identification information. While this architecture implements a useful version of caller identification with call-waiting, it does not teach call-waiting with or without caller identification that includes three-way conversations between a calling third party, a called first party, and a second party who is already engaged in a conversation with the first party.
Therefore, it is an object of this invention to provide an enhanced form of call-waiting with or without caller identification that includes three-way conversations between telephone customers.
It is another object of this invention to provide a method of providing identification information related to a calling third party to a called first party already engaged in a conversation with a second party via a terminating central office and then, in response to a predetermined digit entered on the first party apparatus keypad, connecting the calling third party to the first and second parties for three-way conversations between the first, second and third parties.
It is still another object of this invention to provide a method of connecting a second party who is on hold to a first party who placed the second party on hold and a third party whose incoming call has been answered by the first party for three-way conversations between the first, second and third parties, in response to a predetermined digit entered on the first party apparatus keypad.